Soil retention of aminoplast resin-softener-epichlorohydrin modified cellulosic fabrics obviated by inclusion of carboxymethyl cellulose in reaction system



SOIL RETENTION F AMINOPLAST RESIN-SOFT- ENER-EPICHLOROHYDRIN MODIFIED CELLU- LOSIC FABRICS OBVIATED BY INCLUSION 0F CARBOXYMETHYL CELLULOSE IN REACTION SYSTEM William L. Mauldin, Spartanburg, S.C., assignor to Deering Milliken Research Corporation, Spartanburg, S.C., a corporation of Delaware No Drawing. Continuation of abandoned application Ser. No. 91,307, Feb. 24, 1961. This application Nov. 24, 1965, Ser. No. 511,286

5 Claims. (Cl. 8--115.6)

This application is a continuation of application Ser. No. 91,307, filed Feb. 24, 1961, now abandoned.

This invention relates to an improvement in the process of treating cellulosic materials to impart thereto wrinkle resistance. More particularly, it relates to an improvement in the soiling resistance of cellulosic materials which have been treated with textile resins and/or wet cross linking reagents to impart thereto wrinkle resistance.

The treatment of cellulosic materials, for example textile yarns, thread and fabrics with a textile resin and/ or cross linking reagent to improve the wrinkle resistance of the material is now well known and widely practiced in the textile industries.

It is a common characteristic of these processes that the material thus treated has markedly reduced strength and inferior hand. Strength losses of from to 60% of the strength of the untreated material are common while the hand can become uncomfortable if process controls are not strictly maintained. To partially overcome these losses in strength and hand, the industry commonly applies to the treated material a softener, such as polyethylene, to enhance the strength and hand characteristics. This partial solution to the problems, however, raises one serious disadvantage in that materials so treated tend to pick up a greater amount of soil and retain it even after a plurality of washes. This effect is noticed to a slight extent when cellulosic materials are treated only with textile resins, but is markedly increased in the use of the polyethylene softener.

I have discovered that the soiling properties of resintreated cellulosic material can be considerably improved by adding to the cellulosic material before, during, or after treatment for wrinkle resistance at least about 0.2 part per part of polyethylene, of a cellulosic or starch modifier comprising recurring units of the formula:

or the corresponding hydroxyalkyl. Preferably, the anionic radical comprises being hydrogen or an alkali metal, preferably sodium or potassium. One or more of the free hydrogen atoms in the glucoside .unit may be replaced with a lower alkyl radical such as methyl, ethyl, propyl, isopropyl or butyl. A sufficient number of the above recurring units should be present so that at least about 4%, up to about of the weight of the modifying compound is provided by anionic radicals. Mixtures of the various suitable modifying com- States Patent 0 amaze pounds also may be utilized to produce the desired improvement in soiling properties.

The polyethylene softener is generally applied to the fabric as a component of a conventional textile resin bath and generally I prefer to apply the required amount of additive to the fabric by incorporating this compound into the same bath.

The textile resin bath generally contains from about 1 to about 25 by Weight, preferably 4.5 to 5% of the textile resin, a sufficient amount of catalyst to provide an acid bath, preferably at "a pH of about 5, and a wetting agent, all of these components being intimately dispersed within an aqueous emulsion of polyethylene. Generally, the polyethylene constitutes from about 0.25 to about 5% by weight of the textile resin bath. The required amount of modifier can be "applied to a fabric by incorporating into this bath at least about 0.2 part per part of polyethylene in the bath.

The term resin treatment is one commonly used in the textile art and refers generally to a process whereby a fabric is contacted with a crease-proofing, usually thermo setting, reagent, and an acid acting catalyst if desired, dried, e.g., from room temperature to C., and then cured, i.e., reacted with the fabric in its dry state at a higher temperature, e.g., 140 C. to as high as 200 C., to form chemical cross links between the resin and the free hydroxy groups of the cellulose. At this temperature, the reagent by itself would ordinarily resinify in the presence of the appropriate catalyst, thus probably contributing to the use of the term resin treatment.

Along with the use of the term resin treatment, the textile art also has adopted the practice of using the term textile resin to define the reagents employed in this resin treatment to distinguish them from sizes which merely coat the fibers without reacting therewith, although the term is amisnomer in that in contradistinction to the generally accepted meaning of the tenth resin, these textile resins have relatively low molecular weights, and are always water soluble. Therefore, in conformity with the generally accepted usage in the textile art, the term resin or textile resin, when used herein, defines those classes of reagents commonly employed in the textile art for the resin treatment or crease proofing of fabrics.

These textile resins are all characterized by having functional groups capable of reacting with the hydroxy groups of the cellulosic material, usually to form ether cross links. The term crease-proofing agents has also been applied to these compounds. See Nuessle, Textile Industries, Oct. 1959, pp. 116-127. For other discussions of this class of reagents, see Borghetty, Textile World, 109, 89 (1958); Review of Textile Progress, 1950, p. 350; ibid., 1952, p. 417, ibid, 1955, p. 440; ibid, 1956, p. 406; ibid 1957, p. 399 and ibid, 1958, p. 372, and references cited therein.

The textile resins which can be employed in the process of this invention include the low molecular weight, e.g., usually less than 1,000, water-soluble, acid or acid salt catalyzed materials which are thermosetting in the presence of cellulosic materials as defined hereinafter. See Nuessle, supra. There are many textile resins commercially available. The largest class of known textile resins are the aminoplast resins formed by reacting compounds such as urea and/or melamine with formaldehyde. Specific examples of textile resins within this class include urea formaldehyde textile resins, e.g., dimethylol and trimethylol urea and the resin commercially available from Rohm & Haas under the trade name of Rhonite 610, methyl ethers of urea formaldehydes such as the resin sold by Rohm & Haas under the trade name of -R-2 Resin; acrolein urea formaldehyde resins; cyclic ethylene urea formaldehyde resins, e.g., dimethylol ethylene urea, dimethylol propylene urea, dimethylol dihydroxy ethylene urea, and the resin sold by E. I. du Pont Patented Get. 22, 19 5s" under the trade name of Zeset and the textile resin sold by Rohm & Haas under the name of R-l Resin; trimethylol acetylene diurea; tetramethylol acetylene diurea; melamine formaldehyde textile resins, e.g., dimethylol and tetramethylol melamine, dimethyl tetramethylol melamine, and those sold by Monsanto under the trade names of Resloom HF. and Resloom L.C.; methylated melamine formaldehyde textile resins, e.g. pentamethoxymethyl melamine and the textile resin sold by Monsanto under the trade name of Resloom M-75 Resin; and copolymers of these resins, such as a copolymer of melamine formaldehyde and ethylene urea formaldehyde. Still another class of textile resins which can suitably be employed are the triazone resins, e.g., 1,3 dimethylol methyl perhydrotriazone.

In addition to the textile resins of the above type, one can suitably employ epoxy compounds. See US. Patent No. 2,752,269. Examples of suitable resins of this class include the glycidyl ether of ethylene glycol, the triglycidyl ether of glycerol, the diglycidyl ether of 2,2 bis (p hydroxyphenyl) propane and the epoxy textile resin sold by Shell Chemical Company under the name of Eponite 100. Still another resin which can be employed is the tris (l azirindinyl) phosphine oxide which is prepared by reacting three moles of ethyleneimine with one mole of P001 and which is known to the trade as APO Resin or Imine I.P. Resin.

Other crease proofing agents or textile resins employed to improve the wrinkle resistance of cellulosic materials include the polyglycol acetals (see U. S. Patent No. 2,786,- 081) and the aldehydes, e.g., formaldehyde, glyoxal, glutaraldehyde and a hydroxyaldepaldehyde (Hurwitz et al., Textile Research J. 28,257 (1958) and aldehyde derivatives, e.g., phenol formaldehyde and tetramethylol acetone.

One need not employ a single textile resin but can employ mixtures of the above type resins or copolymers thereof. Likewise, it is not necessary that the resins be entirely free from water-insoluble components since it has been found that dispersed particles of water-insoluble materials in the resin solution are not deleterious. Some of the commercially available resins mentioned above contain small percentages of water-insoluble polymeric materials and while an aqueous mixture of such resins can be filtered if desired, equally satisfactory results are generally obtained by employing the unfiltered material.

As stated above, some textile resins can be catalyzed by an acid-acting catalyst, i.e., acidic in character and others by an alkaline catalyst although most of the textile resins employed today are catalyzed by acid-acting catalysts.

Suitable acid-acting catalysts for resins of the above types are well known in the art. Urea formaldehyde and melamine formaldehyde resins are best catalyzed by hydrochloride or nitrate salts of hydroxyalkyl amines such as monethanolamine hydrochloride or 2 amino 2- methyl propanol hydrochloride or nitrate. Cyclic ethylene urea formaldehyde resins, acetylene diurea formaldehyde and Uron resins are preferably catalyzed by zinc nitrate, zinc fiuoroborate or by magnesium chloride. The epoxy resins are preferably catalyzed by acid fluoride salts, such as the catalyst compositions available from Shell Development Company under the trade names of Curing Agent 48" and Curing Agent 20. Formaldehyde and other aldehydes and aldehyde derivatives are catalyzed with ammonium chloride, magnesium chloride or pyridine chloride.

The amounts of catalyst desirable to be employed are well known in the art. Generally, any amount of catalyst up to about 20% or more by weight of the resin mixture will give satisfactory results with the preferred range being from about 0.5% to about of the resin solids employed.

The term cellulosic material when used herein means any material, preferably textile, comprising fibers having the free hydroxy group characteristics of cellulose, e.g., cotton, unmodified cellulose and cellulose modified by etherification or esterification of a portion of the hydroxy groups. Textile materials within this definition include those comprising natural cellulose fibers, e.g., cotton, linen, jute, flax, regenerated cellulose fibers, e.g., viscose rayon fabrics, and cellulose fibers some of the hydroxy groups of which have been replaced by ester or ether groups, so long as some free hydroxy groups are present so as to obtain the desired cross linkage. Normally, cellulosic fibers which contain as few as 1.8 free hydroxy groups per anhydro-glucose unit will result in sufiicient cross linkage for satisfactory results. Thus, cellulosic textile materials the fibers of which contain a limited number of acetyl groups, such as cellulose acetate fabrics of a relatively low acetyl content, and textile materials the fibers of which contain a limited number of methyl ether groups, such as partially methylated cellulose, can be processed according to this invention. However, textile materials which do not comprise cellulosic fibers having free hydroxy groups are not normally suitable for use in the process of this invention and are not within the term cellulosic material. as used herein.

Although this invention is directed primarily and preferably to cellulosic textile materials, both knitted and woven, the advantages of this invention can also be achieved by treating the cellulosic yarns or threads employed to produce these fabrics. Ordinarily, this will be cotton thread or yarn. The thus treated thread or yarn, when woven into fabric, will provide a fabric having better properties than identical fabric woven from yam or thread resin treated according to prior art procedures.

Satisfactory results, according to this invention, can be achieved by employing cellulosic fabrics containing both cellulosic and noncellulosic fibers, especially if the noncellulosic fibers have some minimum care characteristics of their own. For example, the minimum care characteristics of fabrics formed from a mixture of glycolterephthalate fibers and cotton fibers can be improved by the process of this invention even if the percentage of cotton fibers is small, e.g., 10% to 40%. Satisfactory results can also be obtained with fabrics formed from a mixture of nylon fibers and cellulosic fibers of a mixture of cellulosic fibers and polyaciylic fibers, e.g., those sold under the trademark Orlon.

The improved characteristics of the fabric treated according to the process of this invention will be more readily apparent if the cellulosic, e.g., cotton content of the fabric is substantial, e.g., about 40% or more by Weight. Because woven fabrics consisting essentially of cotton, e.g., -100% cotton, are the ones most frequently treated with a crease-proofing agent, i.e., resin treated, it is to these fabrics that this invention is preferably directed.

After the resin treatment, the cellulosic material may be additionally modified by treatment with a wet cross linking agent, i.e., a reagent which is used to treat cellulosic fibers while they are in a wet, or swollen condition whereby chemical cross links are formed between the cellulose molecules. The activity of these reagents is similar to the action of textile resins but they do not resinify by themselves and consequently have attained a different status in the textile industry. Among the suitable wet cross linking agents there are included epoxides, haloepoxides, and halohydrins in the presence of less than water (calculated on the weight of the dry fabric), and about 2-15 alkali metal hydroxide (calculated on the water present) according to the procedure of Gagarine as disclosed in his US. patent application S.N. 24,265, filed Apr. 25, 1960. The divinyl sulfone-aqueous alkali treatment of wet cross linking agents disclosed in US. Patent No. 2,524,399 is also suitable, as is the formaldehyde treatment disclosed by Guthrie in Textile Research Journal, 29,834 (1959) and an other treatment which reacts wet cellulosic material to improve its wrinkle resistance. In US. application S.N. 77,284 to Gale, additional wet cross linking reagents are disclosed which are sutiable for use in conjunction with this invention.

In those procedures involving caustic treatment before or after application of the wet cross linking agent, the modifier may be added during the caustic treatment if desired. But, as stated above, I prefer to add the modifier to the textile resin bath, not only for ease of operation but also because of the marked improvement in strength and soiling properties obtained when this procedure is used.

At least about 0.2 part of the modifier should be provided per part of polyethylene used. Generally, no more than about 2.0 parts of the modifier per part of polyethylene solids is required for excellent improvement in the soil resistance properties of the fabric. Optimum results are obtained when substantially equal amounts of the desired compound and polyethylene solids are applied to the fabric. In amounts less than about 0.2 part, the treated material picks up and retains nearly as much soil as the untreated material. In amounts greater than about 2 parts, the material picks up and retains even less soil, but the hand and drape of the material is reduced to a degree which is undesirable for wearing apparel, such as shirts. Where these qualities are not required, amounts of the additive up to about parts per part of polyethylene can be used. Obviously, the treated material can be subjected to mechanical treatments, such as with a button breaker, to improve the hand of the treated material without adversely affecting the strength and soiling properties.

Among the modifiers suitable for use in accordance with my invention there are included carboxymethyl cellulose, alkali metal salts, such as sodium and potassium, of carboxymethyl cellulose, and carboxymethyl hydroxyethyl cellulose and other acid derivatives of cellulose or carboxymethyl cellulose, such as the sulfated or phosphated compounds. In addition to the acid-derivatives of cellulose, I have also found that acid-derivatives of starch, such as starch sulfate or phosphate, also provide improvement in the soiling resistance. A particularly desirable starch product is the starch phosphate sold by American Maize Company and having from 8 to 10% phosphate on a weight basis.

Of these compounds, sodium carboxymethyl cellulose is highly preferred for its availability, low cost, high solubility in the resin bath, and outstanding effect on the resin treated fabrics. Two substitution levels of sodium carboxylmethyl cellulose are available (an average of 0.7 and 1.3 of the three available free hydroxy groups per glucose residue are carboxymethyl substituted) and each of these levels are available in various viscosity ranges, low,

medium and high. The low viscosity material, at a 2% concentration in water, has a viscosity less than about 100 centipoises at C., the medium viscosity material havin water, the high viscosity material exceeds 1000 centipoises under the same conditions. At a 1% concentration in water, the high viscosity material exceeds 1000 centipoises, usually up to about 3,000 centipoises, at 25 C. Of these three types, the low viscosity material having a substitution level of 0.7 is more readil compatible with the textile resin bath, and, consequently, is highly preferred.

In the following examples which illustrate preferred embodiments of this invention, the treated fabrics are tested according to accepted standard methods. Tensile strength is determined by ASTM Designation D1682-59T, Grab test G and tear strength is determined by test ASTM Designation D 1424-59.

Example I Low viscosity (substitution level of 0.7) sodium carboxymethyl cellulose (40.0 gms.) is added slowly to 300 gms. of water with high speed stirring to provide a clear solution. A mixture of polyethylene HDE (40.0 gms.) and 13.69 gms. of Surfonic N-95, a condensation product of 9.5 moles ethyleneoxide per mole of nonylphenol, is melted at a temperature of about 130 C. After adding 1.37 gms. of 50% potassium hydroxide to the melt, it is added slowly with continued rapid stirring to the sodium carboxymethyl cellulose solution. To the resulting emulsion is added 35.6 gms. of a modified melamine textile resin (about 50% solids) sold under the trade name of Aerotex A 23 Special Resin, containing 5 gms. of 2-methyl-2-amino-propanol hydrochloride (Catalyst AC). Ten 3 x 3" swatches of 4.00 yard per lb. 80 x 80 bleached printcloth are impregnated with the resulting emulsion (about wet pick-up). After drying at room temperature, the fabric swatches are cured at 350 F. for 1.5 minutes. The samples are then wet with an aqueous solution of 3.0% potassium hydroxide and 1% sulfated cresol wetting agent (Mercerol GV) with a 60% pick-up. About 10% epichlorohydrin, calculated on the dry fabric, is then padded onto the fabric swatches which are then sealed in a polyethylene bag and maintained at 55 C. for 16 hours. The dry tensile strength of each of the treated swatches is materially increased over a control fabric swatch treated in the identical manner except that no sodium carboxymethyl cellulose (CMC) is added to the textile resin bath. The dry tear strength of the samples was substantially maintained in each instance.

All of the 3 x 3" swatches of treated fabric, along with the control swatch, are placed in a Launderometer jar containing 4 gms. of vacuum cleaner dust in 400 milliliters of water. The jar is then secured and oscillated for 30 minutes at 160 F. After rinsing in cool water for five minutes, the fabric swatches are dried and seen to be quite dirty. It is noted, howeevr, that the treated swatches are not nearly as dirty as the untreated swatch.

The dry swatches are then submitted for testing in accordance with AATC Wash Test No. 3, wherein Tide detergent is substituted for the soap of that particular test. After this test the swatches are washed with a 5% solution of acetic acid, rinsed and dried. The treated swatches are seen to retain only a minimal amount of the soil which they contained prior to washing. To the untrained eye, the swatches are as clean as they were prior to soiling in the Launderometer. Even to the most skilled eye, the amount of soil retained is hardly discernible. On the other hand, the control swatch remains substantially soiled even after ten washings in accordance with AATC Wash Test No. 3.

Example II Following the procedure of Example I, a textile bath is prepared containing 9% of a modified melamine textile resin (about 50% solids) sold under the trade name of Aerotex A-23 Special Resin, 1.25% of 2-m'ethyl-2- amino-propanol hydrochloride (Catalyst AC), 0.5% Surfonic N-95 and 6% of a polyethylene emulsion (about 25% by weight polyethylene solids) sold under the trade name of Moropol 700. To the resulting emulsion is added various percentages of low viscosity sodium carboxymethyl cellulose. Swatches 4.0 yard per 1b., x 80 bleached fabric are impregnated with each of the resulting emulsions, cured and treated with 3% sodium hydroxide and epichlorohydrin according to the procedure of Example I. A control fabric is similarly treated except that no sodium carboxymethyl cellulose is added to the textile resin bath. The dry tensile and tear strengths of these samples are given in Table I.

A 20 x 20" swatch of 4.00 yard per lb. 80 x 80 bleached fabric is impregnated with an aqueous solution containing 7 12% of a modified melamine textile resin (about 50% solids) sold under the trademark of Aerotex A-44 and 1 /2 of Accelerator MX, a magnesium chloride catalyst. The sample is padded at 60 lbs. squeeze roll pressure for a 65 to 70% wet pick up and dried on dry cans at 17 lbs. steam pressure. The dry fabric is then cured at 350 F. for 1.5 minutes. To the cured fabric swatch is applied a polyethylene emulsion sold under the trade name of Moropol 700 (about 40 grns. of polyethylene solids) containing about 40 gms. of sodium carboxymethyl cellulose. After drying, the fabric swatch is tested for soil resistance and retention as in Example I and found to exhibit excellent improvement (although not as great as in Example I in this characteristic) when compared to a fabric swatch treated in a similar manner, except that no sodium carboxymethyl cellulose is added to the polyethylene emulsion. The fabric swatches are then treated with sodium hydroxide and epichlorohydrin as in Example I and once again tested for soil resistance and retention. The improvement in these qualities is retained even after this treatment.

Example IV The procedure of Example III is repeated except that the polyethylene emulsion containing the sodium carboxymethyl cellulose is not added to the fabric swatch until after treatment with the sodium hydroxide and epichlorohydrin. Some improvement in the soiling resistance and retention properties is noticed but the effect is not nearly as great as the effect obtained in Example I or in Example III, where the sodium carboxymethyl cellulose is added to the resin bath.

Treatment of fabrics in accordance with my invention greatly diminishes the effects on the fabrics of all type soils, including dry, oily and metallic and the like. I have also discovered that fabric treated in accordance with this invention most surprisingly exhibit less damage from chlorine bleaching than do fabrics treated with resins in the conventional manner. Since chlorine damage is a serious disadvantage in the conventional treatment of fabrics with resins, this improvement constitutes a distinct advantage in the use of my invention.

That which is claimed is:

1. In the process of improving the wrinkle resistance of a cellulosic textile material by impregnating said textile material with an aqueous bath including an aminoplast textile resin, an acid acting catalyst and .a softener, curing the resin on the textile material and applying a wet crosslinking reagent selected from the group consisting of epoxides, haloepoxides, halohydrins and divinyl sulfones, to the textile material while it is swollen and wet with strong caustic, the improvement which comprises applying to the textile material prior to the reaction of said cross-linking reagent therewith, a carboxymethyl cellulose or an alkali metal salt thereof, whereby the soil pickup and retention of the textile material is substantially reduced with considerably less susceptibility to chlorine damage.

2. The process improvement of claim 1 wherein the carboxymethyl cellulose is incorporated in said aqueous bath.

3. In the process of claim 1 wherein the softener comprises a polyethylene emulsion, the improvement which comprises adding to the material the modifier in an amount from about 0.2 to about 2.0 parts per part of polyethylene.

4. The process improvement of claim 1 wherein th modifier comprises sodium carboxymethyl cellulose.

5. The process improvement of claim 1 wherein the wet cross-linking reagent comprises epichlorohydrin.

References Cited UNITED STATES PATENTS 2,512,195 6/1950 Bener 8-1156 2,524,399 10/1950 Schoene et al 8116 2,602,018 7/1952 Beer 8116.3 2,884,413 4/1959 Kerr 260233.5 3,089,747 5/1963 Welch 8--115.6 3,175,875 3/1965 Gagarine 8-116 FOREIGN PATENTS 538,897 8/1941 Great Britain.

OTHER REFERENCES Suter et al.: Laundry Age, Sept. 1951, pp. 18-20.

Mazzeno et al.: American Dycstuff Reporter, May 5, 1958, p. 299-p. 302.

Rosenbaum: American Dyestuif Reporter, May 18, 1959, pp. 46-49.

Stillo et al.: Textile Research Journal, vol. 57, pp. 949- 961 (1957).

Speel et al.: Textile Chemicals and Auxiliaries, second edition, Reinhold, New York, p. 418 (1957).

NORMAN G. TORCHIN, Primary Examiner.

J. C. CANNON, Assistant Examiner. 

1. IN THE PROCESS OF IMPROVING THE WRINKLE RESISTANCE OF A CELLULOSIC TEXTILE MATERIAL BY IMPREGNATING SAID TEXTILE MATERIAL WITH AN AQUEOUS BATH INCLUDING AN AMINOPLAST TEXTILE RESIN, AND ACID ACTING CATALYST AND A SOFTENER, CURING THE RESIN ON THE TEXTILE MATERIAL AND APPLYING A WET CROSSLINKING REAGENT SELECTED FROM THE GROUP CONSISTING OF EPOXIDES, HALOEPOXIDES, HALOHYDRINS AND DIVINYL SULFONES, TO THE TEXTILE MATERIAL WHILE IT IS SWOLLEN AND WET WITH STRONG CAUSTIC, THE IMPROVEMENT WHICH COMPRISES APPLYING TO THE TEXTILE MATERIAL PRIOR TO THE REACTION OF SAID CROSS-LINKING REAGENT THEREWITH, A CARBOXYMETHYL CELLULOSE OR AN ALKALI METAL SALT THEREOF, WHEREBY THE SOIL PICKUP AND RETENTION OF THE TEXTILE MATERIAL IS SUBSTANTIALLY REDUCED WITH CONSIDERABLY LESS SUSCEPTIBILITY TO CHLORINE DAMAGE. 